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The effect of striatal pre‐enkephalin overexpression in the basal ganglia of the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine mouse model of Parkinson's disease
Author(s) -
Bissonnette Stéphanie,
Muratot Sophie,
Vernoux Nathalie,
Bezeau François,
Calon Frédéric,
Hébert Sébastien S.,
Samadi Pershia
Publication year - 2014
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12596
Subject(s) - mptp , striatum , substantia nigra , basal ganglia , enkephalin , endocrinology , globus pallidus , medicine , dopamine , tyrosine hydroxylase , parkinson's disease , proenkephalin , biology , chemistry , dopaminergic , neuroscience , central nervous system , opioid , receptor , disease
The midbrain dopamine (DA) cell death underlying Parkinson's disease (PD) is associated with upregulation of pre‐enkephalin ( pENK ) in striatopallidal neurons. Our previous results obtained with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) parkinsonian monkeys suggest that increased striatal expression of pENK mRNA is a compensatory mechanism to alleviate PD‐related motor symptoms. In this study, we tested the hypothesis that increased pENK expression in the striatum protects against the neurotoxic insults of MPTP in mice. To this end, recombinant adeno‐associated virus serotype 2 also containing green fluorescent protein was used to overexpress pENK prior to DA depletion. Our results showed that overexpression of pENK in the striatum of MPTP mice induced: (i) increased levels of the opioid peptide enkephalin (ENK) in the striatum; (ii) higher densities of ENK‐positive fibers in both the globus pallidus (GP) and the substantia nigra; (iii) higher locomotor activity; and (iv) a higher density of striatal tyrosine hydroxylase‐positive fibers in the striatum. In addition, striatal overexpression of pENK in MPTP ‐treated mice led to 52 and 43% higher DA concentrations and DA turnover, respectively, in the GP compared to sham‐treated MPTP mice. These observations are in agreement with the idea that increased expression of pENK at an early stage of disease can improve PD symptoms.